Various bloods have different antigenic and immune properties. These differences can be observed among different species and also between members of a species. Principally, these differences involve different antigens on the red blood cell wall and the immunological response to these antigens.
Human bloods have different antigenic and immune properties, and the four major groups are distinguished from each other by the presence or absence in the red blood cells of different, but related, antigens. Blood of group A contains antigen A, blood of group B contains only antigen B, blood of group O contains neither antigen A nor antigen B, and blood group AB contains only antigen AB.
Blood groups in cats, however, are different from blood groups in man. In cats two major feline blood groups were discovered in the 1950's with naturally occurring antibodies. The two feline erythrocyte antigens were designated A and B. Blood type B is rare in domestic cats, but is found in a much higher percentage in certain feline breeds. U. Giger et al., Frequency of Feline Blood Groups in the United States, J. Am. Vet. Med. Assoc. 1989; 195:1230-1232.
The presence in the cells of the antigens which are capable of immunological reaction with their respective antibodies, makes the cells susceptible to agglutination. When an antigen is not present in the red blood cell, the respective antibodies, called agglutinins, develop in blood plasma. Thus, for example, in man blood of group A contains anti-B antibodies in its serum and group O blood contains both anti-A and anti-B agglutinins. If bloods are mismatched, so that anti-A or anti-B antibodies are mixed with red blood cells containing A or B antigens, respectively, the red cells will agglutinate due to the immunological antigen/antibody reaction. This causes the cells to clump and thus block vessels, with usually fatal results.
Blood type B is a rare blood type in domestic cats, but is found in much higher percentage in certain feline breeds. U. Giger, et al. Frequencies of Feline Blood Groups in the United States, J. Am. Vet. Med. Assoc. 1989; 195:1230-1232. If a cat with blood type B is transfused with blood from a cat with blood type A, a serious life-threatening reaction may occur. In particular, if a female cat with blood type B is mated to a male cat with blood type A, the kittens may have neonatal isoerythrolysis and die. Neonatal isoerythrolysis is similar to Rh incompatibility in man. G. Cain et al., Presumptive Neonatal Isoerythrolysis in Cats, J. Am. Vet. Med. Assoc. 1985; 187:46-48; M. Huber et al., Feline Neonatal Isoerythrolysis in Two Litters, J. Small Anim. Pract. 1987; 28:833-838.
Agglutination reactions are widely used in biology and medicine to detect antibody or antigen molecules. Agglutination reactions usually involve the in vitro aggregation of microscopic carrier particles which bear on their surface antigenic molecules. An agglutination reaction can be caused by antibody molecules specifically corresponding to the antigen, an antigen, if the carrier particle is antibody coated or a protein that reacts with the surface antigenic molecules. The carrier particles include red blood cells, bacteria and polystyrene spheres. Blood typing makes use of this phenomena of agglutination to identify a cell type. In particular, feline blood type B is determined with antibodies produced in cats with blood type A. Cats of blood type A are immunized with B antigen. Antibodies against B antigen are produced by these cats. These antibodies are admixed with feline blood and theoretically agglutination should occur if B type antigens are present on the erythrocytes. In practice, however, these antibodies have been observed to be weak and unstable. See Giger, supra at 1231.
Consequently, a need exists to develop a reliable method to identify feline blood type B to decrease transfusion reactions and to be used to diagnose and prevent hemolytic disease in newborn cats.